Specifies the percentage of each table to sample when generating queries using the TABLESAMPLE clause.

Data Type

string

Default Value

""

Remarks

When this property is set to a value greater than 0, the server adds a TABLESAMPLE SYSTEM (n PERCENT) clause to eligible table references during query generation.

/* Input SQL */
SELECT * FROM `tbl`

/* Generated Google BigQuery SQL when TableSamplePercent=10 */
SELECT * FROM `tbl` TABLESAMPLE SYSTEM (10 PERCENT)

This instructs Google BigQuery to return a sample of approximately the specified percentage of rows.

Use this property to limit result size during exploration or testing of large tables. Set a value between 1 and 100 to indicate the sampling percentage.

Limitations:

• This property affects only generated SQL and has no effect when QueryPassthrough is enabled.
• The actual number of rows returned may exceed the specified percentage depending on how Google BigQuery implements sampling.
• The TABLESAMPLE clause is not supported on views. The server omits the clause when generating queries against views.